Historically, vascular procedures have been performed using open surgical techniques requiring extensive incisions and operating room time. As instruments became miniaturized, a variety of other therapeutic options have arisen. Examples include: balloon angioplasty, atherectomy, stent placement, laser ablation, stent graft placement, intraluminal ultrasound, and angioscopy. Guidewires have had a place in all of these applications. The guidewires serve as a conduit in the vascular circulation for the introduction of catheters, cutting devices, fiber optics, and ultrasound probes. Additionally, similar advances have been made in the hepato-biliary tree.sup.(4,5,6,7), the genito-urinary .sup.(8,9,10,11) and the gastro-intestinal systems for treatment of tumors and other obstructive lesions.
Occasionally, the need has arisen to perform a therapeutic intervention from two ends of the effected site in the vascular system. This has required passing a guidewire from two access points.sup.(1). Presently, a guidewire is introduced from one access point and the distal end is physically grasped and pulled across the vascular system by a device such as the snare type probe.sup.(2) inserted at a second site. The procedure to grasp the distal end is time consuming and requires dexterity on the part of the physician performing the procedure. The lengthy visualization by means of a fluoroscope, necessary to carry out this procedure, exposes the patient to dosages of X-ray radiation which would otherwise be unnecessary. The device we describe in this patent shortens the time and greatly facilitates the procedure for placing a single guidewire, or a monorail, which traverses the vascular system from one access site to another.